Recently, ferromagnetic alloys (Fe-Ga) have been developed for use as transduction material under tensile loading as wire cables or bars for example, because of their high physical tensile strength and magnetostrictive property. However certain problems arise during such tensile loading because of the rotation of the material magnetization toward the physical loading stress axis. Such magnetization rotation under loading was undesirable because magnetization becomes axially aligned with the tensile stress so as to preclude any magnetostrictive change in material length under an axially applied magnetic field.
Compressive stress was applied during annealing treatment to magnetostrictive material such as Terfenol-D according to U.S. Pat. No. 6,139,648, the entire contents of which are incorporated herein by reference, so as to maximize magnetostriction during use in transducers or the like. However, because magnetostrictive materials similar to Terfenol-D are brittle, they cannot be used in environments subject to significant tensile loading.
The present invention is the use of positive magnetostrictive materials under tensile loading conditions.